Numerous biophysical and structural factors contribute to the host response to implantable biomaterials including material composition, mechanical properties, molecular landscape, ability to resist infection, proper surgical use and, importantly, surface topography. Surface topography is a key aspect regulating the tissue-implant interface and is increasingly being recognized as an important factor to control the response of cells to biomaterials such as natural or artificial membranes, short term and long term implants and other medical devices. Evidence has shown that multiple grooved surfaces of various dimensions and geometries exert topographical control over the behavior of cells interacting with that surface. The interaction and response of cells to these topographies are mediated through a phenomenon called contact guidance. The impact of surface topography on cellular function has been recognized and demonstrated to be capable of orienting cell migration and differentiation in a manner that would aid in guided tissue repair. This topographical control has numerous well researched benefits including enhanced re-epithelialization rates, directed cellular orientation and migration and increased cell migration speed/velocity in addition to other benefits.
Various fabrication techniques are known in the art for producing microstructured topographies. For example, random microtopographies have been added to implant surfaces through various well known methods including sandblasting, acid etching, machining, grinding, abrasion and plasma spraying. While these surface modifications have important benefits, the resulting topography is structured randomly. In contrast, microfabrication techniques have been shown to produce regular and repeating ordered structures such as microgrooves and pillars. The introduction of these microfabrication techniques have made it possible to regulate cell to cell and cell to substrate interactions in laboratory experiments as well as on medical devices.
The earliest of these microfabrication techniques was photolithography, and the art has since evolved with more complicated techniques including chemical etching, deep reactive ion etching and reactive ion etching, stereolithography, two photon absorption lithography, and laser ablation, among others. Typically, these microfabrication techniques are expensive, time consuming and cannot be performed by a clinician at the time of surgical implantation.
Many soft and pliable medical devices are currently used in medical and dental applications, particularly in guided bone regeneration (GBR) and guided tissue regeneration (GTR) procedures performed by dentists in the form of membranes. These soft barrier membranes are composed of one or more of at least a dozen different types of biomaterials, and can be natural and resorbable (composed of collagen, chitosan, gelatin, etc.), synthetic and resorbable (composed of Ploylactic acid, polylactic/polyglycolic acid, other polymer composites, etc.), or synthetic and non-resorbable (most often composed of polytetrafluoroethylene). The theory of GTR and GBR is predicated on the migration of pluripotential and osteogenic cells from the periosteum and adjacent alveolar bone to the defect site while at the same time excluding epithelial cells and fibroblasts from infiltrating and potentially disrupting new bone formation. In this way, wound healing can be described as a race between a variety of cells to the healing site. The purpose of an occlusive membrane barrier is to keep epithelial cells and fibroblasts on the soft tissue side of the membrane, which enables the healing wound region on the bone side of the membrane to be populated by cells that are more favorable for bone regeneration. There currently exists a need for a hand operated tool that would allow a clinician to emboss a membrane or other soft pliable implant with a microtopography that would orient and direct the migration of these epithelial cells and fibroblasts in manners that would be more conducive to wound healing.